Copying machine provided with a recirculating document feeder apparatus

Abstract

In a copying machine provided with a recirculating document feeding apparatus (RDH), the time required for the overall copying operation is reduced. In the copying machine provided with the RDH, there are cases where the copying operation is started after the number of the documents is counted. Maximum transporting speed of the document in the copying operation is a speed determined in accordance with minimum copying magnification. However, since the transporting speed of the document be set higher than the speed determined in accordance with the minimum copying magnification, the time required for the counting operation can be reduced. Thereby, the time required for the overall copying operation can be reduced.

What is claimed is: 
     
       1. A copying machine for making duplex copies from a series of simplex documents, comprising: means for selecting one of a plurality of copying modes including standard, reduction and enlargement;   means for setting a desired copying magnification;   a rotatable photoreceptor for receiving an image from a document at a first reading station;   a recirculating document feeding apparatus for transporting sheets of documents placed in containing means sequentially to the first reading station at a speed determined by the copying magnification set by said setting means and the copying mode selected by said selecting means and for returning the document to the containing means;   controlling means for performing a counting operation of said series of simplex documents beginning with a last one of said simplex documents, said controlling means performing said counting operation by operating said recirculating document feeding apparatus at a speed higher than a speed corresponding to the reduction mode with minimum magnification; and   means for determining whether copying of the last one of said series to simplex documents should begin on a first side of a copy of a second side of the copy depending on whether the count obtained in said counting operation is odd or even;   wherein said recirculating document feeding apparatus comprises an endless transport belt mounted on a plurality of rollers beneath the containing means and having an upper portion stretched between two of said rollers, said upper portion serving as a placing member for returning documents to and supporting documents in said containing means;   wherein said copying machine may also be used for copying duplex documents, said copying machine further comprising a second reading station and a document inverting means for inverting documents between said first reading station and said second reading station.   
     
     
       2. The copying machine of claim 1 further comprising a first support cylinder positioned over said first reading station and a second support cylinder positioned above said second reading station, said first and second support cylinders being rotated in synchronization with the speed determined by the copying magnification set by said setting means and the copying mode selected by said selecting means when documents are being copied and being rotated at a maximum speed during the counting operation. 
     
     
       3. A document transporting apparatus comprising: containing means for holding a stack of documents;   feed means for picking off an uppermost document from said stack of documents;   separating means for receiving the uppermost document from said feed means and for returning any additional documents stuck beneath the uppermost document to said containing means;   a first support cylinder positioned above a first reading station;   a transporting path for moving documents received from said separating means to said first support cylinder;   an endless transport belt mounted on a plurality of rollers beneath the containing means and having an upper portion stretched between two of said rollers, said upper portion serving as a placing member for returning documents to and supporting documents in said containing means;   means for transporting documents from said first support cylinder onto said endless transport belt; and   controlling means for performing a counting operation of said stack of documents before performing a synchronized transport of documents to said first reading section, said controlling means performing said counting operation by operating said document transporting apparatus at a maximum speed higher than any speed for performing a synchronized transport of documents to said first reading station;   wherein said means for transporting documents comprises a second support cylinder and means for inverting documents received from said first support cylinder and for providing inverted documents to said second support cylinder.